add script to autogenerate help from man pages

This creates main help like:
--
usage: apk [<OPTIONS>...] COMMAND [<ARGUMENTS>...]

Package installation and removal:
  add        Add packages to WORLD and commit changes
  del        Remove packages from WORLD and commit changes

System maintenance:
  fix        Check WORLD against the system and ensure consistency
  update     Update repository indexes
  upgrade    Install upgrades available from repositories
  cache      Commands related to the management of an offline package cache

Querying package information:
  info       Give detailed information about packages or repositories
  list       List packages matching a pattern or other criteria
  dot        Generate graphviz graphs
  policy     Show repository policy for packages

Repository maintenance:
  index      Create repository index file from packages
  fetch      Download packages from global repositories to a local directory
  manifest   Show checksums of package contents
  verify     Verify package integrity and signature

Miscellaneous:
  audit      Audit directories for changes
  stats      Show statistics about repositories and installations
  version    Compare package versions or perform tests on version strings

This apk has coffee making abilities.
--

And applet specific help like:
--
usage: apk add [<OPTIONS>...] PACKAGES...

Description:
  apk add adds the requested packages to WORLD and installs (or upgrades)
  them if not already present, ensuring all dependencies are met.

Options:
  --initdb         Initialize a new package database
  -l, --latest     Disables normal heuristics for choosing which repository to install a
  -u, --upgrade    When adding packages which are already installed, upgrade them rather
  -t, --virtual NAME
                   Instead of adding the specified packages to WORLD, create a new
  --no-chown       Do not change file owner or group
--

1 files changed, 1 insertions, 3 deletions

diff --git a/src/app_fetch.c b/src/app_fetch.c
index 677fabf..224618b 100644
--- a/src/app_fetch.c
+++ b/src/app_fetch.c
@@ -96,7 +96,7 @@ static const struct apk_option options_applet[] = {
 	{ 'R', "recursive" },
 	{ 0x104, "simulate" },
 	{ 's', "stdout" },
-	{ 'o', "output", required_argument, "DIR" },
+	{ 'o', "output", required_argument },
 };
 
 static const struct apk_option_group optgroup_applet = {
@@ -343,9 +343,7 @@ static int fetch_main(void *pctx, struct apk_database *db, struct apk_string_arr
 
 static struct apk_applet apk_fetch = {
 	.name = "fetch",
-	.arguments = "PACKAGE...",
 	.open_flags =	APK_OPENF_READ | APK_OPENF_NO_STATE,
-	.command_groups = APK_COMMAND_GROUP_REPO,
 	.context_size = sizeof(struct fetch_ctx),
 	.optgroups = { &optgroup_global, &optgroup_applet },
 	.main = fetch_main,